Two blinkies, one high and one low, is an excellent idea. Drivers not only see the two lights, they don't understand what they're looking at and then they have to think it over for a moment. They are, then, much more likely to move over.
Around here, with the two blinkies, drivers think I'm operating some sort of farm equipment along the side of the road. If you know about farm equipment, you know that it's not lit up all that well, and it can be a lot wider than a car. Drivers know it too, so they slow down a *lot* coming up behind me.
There's a similar effect that can be had in front. If you supplement a bright bar light with a headlamp, you get attention, and respect, from oncoming motorists.